Let-off means for looms



Aug. 11, 19250 1,548,996 w. HARRIS LET-OFF MEANS FOR LOOMS Original Filed Dec. 14. 1923 WI TNESS ATTORNEY Patented Aug. ll, 1925.

UNITE STATES P A T E WILLIAM HARRIS, OF PATERSON, NEW JERSEY.

LET-OFF MEANS FOR LOOIVIS.

Application filed December 14, 1923, Serial No. 680,602. Renewed January 26, 1925.

To all whom it may concern:

Be it known that 1, WILLIAM HARRIS, a citizen of the United States, residing at Paterson, in the county of Pass-aic and State of New Jersey, have invented certain new and useful TIHPI'OVGHIBDtS in Let-Off Means for Looms, of which the following is a specification.

In an application for Letters Patent of the United States executed by me on. even date herewith, Serial No. 680,601, I have set forth. a let-off mechanism for looms which in one form thereof included a flexible attenuated tensioning connection between a part of the rotary warp-supply means of a loom and a rotary member confined to rotate in synchrony with the means for exerting a pull on the warp to cause 'it to unwind from the element of the warpsupply means on which the warp is wound, said connection being in permanent tractive engagement with said part and extending therefrom relatively reversely to the direction in which the warp extends from said element and being also in tractive engagement with said member and arranged to paid out thereby when the second-named means is exerting a pull on the warp; in that case the tractive engagement was obtained in each instance by forming the connection with ends and coiling the ends around said part and member, one end portion thereof winding up on said part and the other unwinding from said member as the warp is pulled from the supply means. In the present construction I form the connection endless, which has the advantage that the necessity for rehabilitating the con nection from time to time because it becomes wound up on said part and unwound from said member is avoided. In this construction I further provide for different diameters or steps as to either said part or the part of said member with which the tensioning connection is in tractive engagement so that the connection may be first engaged with one of these steps and, as the weaving proceeds, then with the other, all with an object in view which will hereinafter appear. As to this feature I remark that it is not material to the invention whether the tensioning is endless or even flexible.

The drawing shows my invention in side elevation in operative association with a loom.

In a frame or other support a are the breast-beam and a roller 0 over which the warp A (having interwoven with it the weft or filling and so as to its forward portion being a part of the fabric B) is extended as usual. At the front of the loom is arranged a take-up mechanism of any usual form, the same being here represented by a sand-roller (Z and a cloth-beam e on which to wind up the part of the warp with which the weft or filling has been incorporated to form the fabric, the latter being maintained in a bend around the sand-roller by two other rollers f, as usual. The sandroller is kept from backward rotation by any suitable means, here shown as a holding pawl d engaging a ratchet d fixed to rotate with the sand-roller. It is not material to the present invention in what manner or by what means the sand-roller and beam e are rotated to advance and wind up the fabric.

At the rear of the loom is journaled the warp-beam g. It has on the end of one of its gudgeons h and in the present example constituting a separately formed part a wheel 2' in the form of av sprocket wheel, which in the present example is arranged outward of the loom frame.

On the sand-roller shaft is another such wheel for-med stepped as at 71: 7c and here of the sprocket type.

The aforementioned flexible attenuated tensioning connection is here shown as comprising an endless sprocket chain Z, which is in tractive engagement with the wheel 71 and with one of the steps of wheel Is -70 and which extends over two guides (here pulleys Z Z on frame a), and tension means engaged with a bight or bend Z in the chain depending between the two guides, said means here including a weight-carrier 4n carrying one or more weights at and havmg a pulley 0 engaged in the bend. The said connection extends from wheel z' relatively reversely to the direction in which the warp A is wound on the beam 9 (a good tractive engagement between the same and the wheel being maintained by idler wheels p) and it extends from wheel 7fi'-70 relatively reversely to the direction in which the warp is advanced by the sand-roller; in other words, the relation of the connection to the two wheels 2' and 70 70 is such that when the warp is pulled forward, as by the sand-roller, and so is unwound from the beam g, the chain travels in the direction of the arrow shown, being paid out at 75-70 as it is taken up at i, the weight all the while keeping the chain taut and thus acting on both ends of the warp to maintain the desired tension on the warp.

The improved let-olf mechanism is used as follows: The warp is advanced by the sand-roller, as usual, at a constant speed. But the wound mass of warp on the beam diminishes in diameter, so that the rotation of the beam is constantly accelerated. Therefore, any initial slack in the chain represented by bight or bend Z will in time be taken up because the speed of wheel 2' is accelerating while that of /c]c is constant. At the outset, the chain is made to engage the smaller step 70 of the wheel 'Z370, but when the slack at Z is about to be expended the weaver shifts the chain to the next larger step so that for a time at least the rate of advance of the chain at k ic will be increased and so there will now ensue an augmentation of slack. There may of course be any number of steps to wheel lc7c, depending upon the length of warp usually used in the loom.

The chain being endless in the present example it remains interminably operative so long, at least, as it is shifted from one step to another at lc7c when necessary; and when the slack therein at Z is taken up slack accumulates at Z the latter slack being expended when the slack at Z is forming.

It is obvious that it is not material whether the stepped formation is applied to the lct-ofl' mechanism (as at i) or to the take-up mechanism (as at 7.2'-71:, the actual condition shown and described).

By the term permanent tractive engagement as herein used I mean a tractive engagement not permitting slippage; this is obtained in the example described an d shown by toothed sprocket wheels and a chain engaged therewith.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a loom, the combination of a support, rotary means to supply the warp journaled in said support and including a rotary element on which the warp is wound, means to exert a pull on the warp and thereby unwind it from said element, causing rotation of the first means, a rotary paying-out means confined to rot-ate in synchrony with the second-named means, and an endless flexible tensioning connection in permanent tractire engagement with a part of the first means and a part of the paying-out means and imparting force to rotate the former part relatively contrary to the pull of the warp and to rotate the latter part in relatively the same direction as the warp is pulled.

2. In a loom, the combination of a support, rotary means to supply the warp journaled in said support and including a rotary element on which the warp is wound, means to exert a pull on the warp and thereby unwind it from said element, causing rotation of the first means, a rotary paying-out means confined to rotate in synchrony with the second-named means, and a tensioning connection in permanent tractive engagement with a part of the first means and a part of the paying-out means and imparting force to rotate the former part relatively contrary to the pull of the warp and to rotate the latter part in relatively the same direction the warp is pulled, and one of said parts including steps with either of which said connection may be tractively engaged at will.

In testimony whereof I aliix my signature.

IVILLIAM HARRIS. 

